Dayz Mod runs as a modification of Arma2 Operation Arrowhead and requires BOTH Arma2 and Arma2OA to be installed. There are several versions of the Dayz mod available: Dayz, Epoch and Overpoch. Which one you want to run is up to you and they can all be installed from the Addons button.
Your Dayz mod server will run on a port and will be shown on your servers Game Monitor page. The Query Port is your server port +1 so if the server port is 2302, the query port will be 2303.